Poster No:
2014
Submission Type:
Abstract Submission
Authors:
Rui Dai1, Hyunwoo Jang1, Anthony Hudetz1, Zirui Huang1, George Mashour1
Institutions:
1University of Michigan, Ann Arbor, MI
First Author:
Rui Dai
University of Michigan
Ann Arbor, MI
Co-Author(s):
Introduction:
Understanding neural mechanisms of consciousness remains a challenging question in neuroscience. A central debate in the field concerns whether consciousness arises from global interactions that involve multiple brain regions or focal neural activity, such as in sensory cortex. Additionally, global theories diverge between the Global Neuronal Workspace (GNW) hypothesis (Dehaene, 2011; Mashour, 2020), which emphasizes frontal and parietal areas, and the Integrated Information Theory (IIT) (Tononi, 2016), which focuses on information integration within posterior cortical regions.
Methods:
To disentangle the global vs. local and frontoparietal vs. posterior dilemmas, we measured global functional connectivity and local neural synchrony with functional magnetic resonance imaging (fMRI) data across a spectrum of conscious states in humans induced by psychedelics, sleep, and deep sedation. We utilized between-network functional connectivity as a global metric, and regional homogeneity as a local metric. We further examined functional connectivity across different states of consciousness by analyzing the brain based on its anatomical axis (anterior to posterior) and functional axis (from unimodal to transmodal) (Margulies, 2016). We incorporated a functional integration index (i.e., shortest path length) to assess the efficiency of information transfer between regions. We also evaluated the feature importance of functional connectivity profiles in distinguishing different conscious states.
Results:
We found that psychedelic states are associated with increased global functional connectivity and decreased local neural synchrony. In contrast, non-REM sleep and deep sedation displayed the opposite pattern, suggesting that consciousness arises from global brain network interactions rather than localized activity. This mirror-image pattern between enhanced and diminished states was observed in both anterior-posterior (A-P) and posterior-posterior (P-P) brain regions but not within the anterior part of the brain alone. Moreover, anterior transmodal regions played a key role in A-P connectivity, while both posterior transmodal and posterior unimodal regions were critical for P-P connectivity.
Conclusions:
Overall, these findings provide empirical evidence supporting global theories of consciousness in relation to varying states of consciousness. They also bridge the gap between two prominent theories, GNW and IIT, by demonstrating how different theories can converge on shared neuronal mechanisms.
Novel Imaging Acquisition Methods:
BOLD fMRI 2
Perception, Attention and Motor Behavior:
Consciousness and Awareness 1
Keywords:
Consciousness
1|2Indicates the priority used for review
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Please indicate below if your study was a "resting state" or "task-activation” study.
Resting state
Healthy subjects only or patients (note that patient studies may also involve healthy subjects):
Healthy subjects
Was this research conducted in the United States?
Yes
Are you Internal Review Board (IRB) certified?
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Yes, I have IRB or AUCC approval
Were any human subjects research approved by the relevant Institutional Review Board or ethics panel?
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Yes
Were any animal research approved by the relevant IACUC or other animal research panel?
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Not applicable
Please indicate which methods were used in your research:
Functional MRI
For human MRI, what field strength scanner do you use?
3.0T
Which processing packages did you use for your study?
AFNI
Provide references using APA citation style.
Dehaene, S. (2011). Experimental and theoretical approaches to conscious processing. Neuron, 70(2), 200–227.
Margulies, D. S. (2016). Situating the default-mode network along a principal gradient of macroscale cortical organization. Proceedings of the National Academy of Sciences of the United States of America, 113(44), 12574–12579.
Mashour, G. A. (2020). Conscious processing and the global neuronal workspace hypothesis. Neuron, 105(5), 776–798.
Tononi, G. (2016). Integrated information theory: From consciousness to its physical substrate. Nature Reviews Neuroscience, 17(7), 450–461.
No